Well fishing tool



April l, 1941.

J. E. NICHOLS WELL FISHING TOOL Filed Sept. 27, 1938 l INVENTOR PatentedApryl, 1941 UNITEDSTATES PATENT OFFICE WELL FISHING TOOL Joe E. Nichols,Coalinga, Calif.

Application September 27, 1938, Serial No. 231,925

6 Claims.

This invention relates to a shing tool for recovering small articles,such as drill bit cones. from the bottom of deep wells and particularlyrefers to a device which is actuated by fluid or hydrauic pressurethrough the conventional string of drill pipe and is positivelycontrolled from the drilling floor at the surface of the earth.

During the drilling of deep wells, particularly with cone type bits orothers having small parts, there may accumulate in the bottom of thehole a number of such parts, usually of very hard substances, whichmaterially hinder drilling operations. This invention comprehendsbroadly a shing tool which may be run to the bottom of the hole on aconventional string of hollow drill pipe and there be actuated byhydraulic pressure applied by the drilling fluid, compressed air, orgas, to extend downwardly a plurality of spring ngers to surround andgrasp the so-called fish and retain it so that it may be withdrawn fromthe Well. l

A further object of the invention is to provide a simple and inexpensivefishing tool that will automatically indicate to the operator whether ornot the sh has been secured.

Another object is to provide a hydraulically actuated fishing tool thatwill permit drainage of drilling mud or uid from the drill pipe as thelatter is withdrawn from the well bore.

vAnother object is to provide a fishing tool that I may be repeatedlyactuated at the bottom of the wellso that if the fish is not secured atthe rst attempt the device and the drill pipe supporting it will nothave to be taken out of the well to be reset.

`These and other objects and advantages will be more fully apparent fromthe following description and from the accompanying drawingwhich forms apart of this specification and illustrates a preferred embodiment of theinvention.

In the drawing,

Figure 1 is a longitudinal sectional view of a fishing toolconstructedaccording to this invention, with the operating parts intheir retracted position.

Figure 2 is a longitudinal sectional view of the same device shown inFigure 1, with the parts in extended position ready to surround and pickup the sh.

Referring to the drawing, and particularly to Figure l, referencenumeral I0 designates the generally cylindrical body of the device,which is usuallly reduced in diameter at II and is threaded at I2 toreceive a correspondingly threaded tool joint of a conventional stringof drill pipe, by means of which the device is inserted into andwithdrawn from the well bore. The bore I3 of body I0 is preferablysmoothly nished and extends from an upper shoulder I4 to a lowerthreaded section I5, the latter adapted to receive a similarlythreadedguide bushing I6 which may retain thev operating parts in thebody. Near the upper end of bore I3 are one or more fluid ports- IIwhich are normally closed olf by a tubular valve I8 when the device isbeing run into the well bore in its retracted position.

Valve I8 rests upon or is secured to a piston generally designated I9,and which is composed of an upper plate 20, a resilient packing 2l, anda lower plate 22, the plates being secured together as by bolts 23.Upper plate 2|) is preferably recessed as at 24 and is provided with acentral downwardly extending wash pipe or tube 25, the latter extendingthrough piston I9 and .being provided at its upper end with a seat 28for a valve member such as a ball 21, the purpose of which will bedescribed below.

Extending downwardly from piston I9, and in this case from lower plate22, are a plurality of circumferentially spaced resilient or springngers 28, shaped substantially as shown and, in their retracted positionillustrated in Figure 1, being compressed together and retained at theirlower ends by the bore 29 of bushing I6. In order to retain valve I8,piston I9, and spring fingers 28 in their retracted position, there isprovided an elastic means such as springs 30 and 3|, guided by members32, 33 and 3l, all of which move freely within bore I3 of body I Il.These springs are preferably of such size that they will exert aconsiderable force to urge the piston I9 and the lingers 28 upwardly, todisplace outwardly through ports I1 any mud or drilling fluid that maybe above the piston, and to securelyhold any sh that may be grasped bythat portion of spring lingers below bushing I8.

The lower end of body I0 is preferably notched or serrated as at 35, sothat it may be used to Y e drill through minor obstructions or so-caledbridges in the well bore, and also to agitate cuttings that may havesettled around the Ilsh so that such cuttings may be removed and Washedupwardly by uid passing through the wash pipe 25. Also, it is desirablethat bushing I 6 be spaced somewhat above the bottom of body I8 to forma chamberv into which the sh may enter during such cleaning operationsand into which said fish may be drawn while the device is being removedfrom the well bore.

In operation, the body III, in the condition shown in Figure 1, isattached to the lower end of a conventional string of drill pipe, towhich is connected the usual mud fluid pumps, rotating and hoistingmeans and other apparatus used for rotary drilling. and the tool islowered to the bottom of the well bore. Bridges or other obstructionsare cleaned out by rotating the tool and circulating mud fluid, gas, orwater downwardly through the drill pipe and through wash pipe 25.Springs 30 and II serve to keep the piston I8, valve I8 and fingers 28in their upper or retracted position during such operations. Aftercavings or cuttings have been washed or blown away from around the fishto be recovered, the tool is lifted a few feet oi! bottom. and ballvalve 21 is dropped into the drill pipe, passing downward through themud fluid until it rests on seat 26 of piston I8. The tool is thenlowered nearly to bottom, the distance above the bottom being about thedistance to which spring fingers 2l may be extended as shown in Figure2. The pressure on the drilling mud, or whatever fluid pressure is beingused to actuate the tool, is increased, driving piston I8 downwardlyagainst the springs 30 and 3|, and extending spring fingers 28downwardly to surround the fish sme mnd win be released through ports l1as soon as valve I8 moves downward from the position shown in Figure 1,and the area of these ports should be so proportioned to the duid flowthat adequate pressure drop therethrough will be provided to compresssprings 3 0 and 3l to the desired point.

The tool is then lowered a slight amount to bend inwardly the lower endsof ngers 28, after which the pressure on the actuating fluid isreleased. This will permit the springs 30 and 2| to expand, raising thepiston. I8, valve I8 and spring fingers 28, the latter being squeezedtogether by the bore 28 of lower bushing I6 to constrict the fingersabout the fish. If the operation is not successful, valve I8 will beraised by piston I8 and springs 30 and 3| to its original position tocover ports I1, and this will be indicated to the operator by failure ofthe liquid level in the drill pipe to fall when the latter is raised.The operations just outlined, namely, increasing the pressure to extendfingers 28, followed by a release of pressure to retract the latter, maybe repeated until the ish is secured, without removing the entire tooland string of drill pipe from the well bore.

If the sh is caught by the lower ends of fingers 28, it will prevent thelatter from being drawn through bore 28 of bushing |6so that piston I8and valve I8 will be unable to move to their uppermost position. PortsI1 will thus be left open to drain the drill pipe, as successive lengthsare removed from the well. If the fish is quite small, valve I8 mayalmost reach its uppermost position, in which case the unequallydisposed spaces between prongs 38 at the top of valve I8 will permitdrainage through at least one of ports I1.

It is obvious that many alterations and changes could be made in thearrangement show-n without departing from the essential features of theinvention, and all such modifications as fall within the scope of theappended claims are embraced thereby.

Iciaim:

1. A well lfishing tool comprising a tubular body adapted to beintroduced into a well bore on a drill pipe, a piston in said body, aplurality of circumferentially spaced spring fingers extendingdownwardly from said piston and adapted to be extended out of said bodywhen fluid pressure is admitted thereto above said piston, a springurging said piston and said fingers toward their retracted position, afluid passage through said piston, and means operable from the upper endof said drill pipe for controlling iiuid flow through said passage.

2. A well fishing tool according to claim 1 with the addition of a drainport in said body above said piston and a sleeve extending upwardly fromsaid piston for opening and closing said port.

3. A well fishing tool according to claim l with the addition of guidemeans in said body cooperating with said spring fingers, so constructedand arranged that said fingers will expand outwardly as they areextended from said body and will contract inwardly as they are retractedwithin said body.

4. A weil shing tool according to claim l, in which the upper face ofsaid piston is provided with a valve seat in said fluid passage, andsaid ow control means constitutes a ball adapted to be passed downwardlythrough said drill pipe to rest on said valve seat.

5. A wellfishing tool according to claim 1 in which said body extendsdownwardly below said fingers when the latter are in their retractedposition, to form a chamber into which said fingers may draw an objectto be withdrawn from said well bore.

, pressure on said piston, cutting means at the lower end of said bodyspaced from the lower end of vsaid resilient fingers in their retractedposition to clear an annular space below the ob- `iect to be grasped bysaid fingers so that they may encircle the same when they are extendedfrom said body, and guide means in said body spaced abovethe lower endof said fingers to contract the same inwardly as they are re tracted bysaid piston.

JOE E. NICHOLS.

